I still think the only thing to do now is to switch Linux over to Qt. I think the main barrier would be that Qt has no support for C, so I got started on binding Qt's C++ code to C after making my last comment. The bindings are almost half complete. As Ovation1357 said, the Linux community is still bound by the managers of core utilities like GTK, even if they are called "community maintained". The best way to avoid this would be to make future libraries use compatible syntax so that they can be swapped seamlessly by users. For example, if future toolkits used the same syntax for functions as GTK or Qt but had additional features that those toolkit lacked, then apps that use GTK or Qt could switch without doing a full rewrite of their GUI code, and users could switch between the 2 without the app even noticing.
Anyways, this isn't how things are today and developers still have to choose which toolkit to use from the very beginning, so Qt at least has to be an option. I'll try to finish the bindings as soon as possible and I'll report back to this forum once they're complete.